Twist latch



June 2, 1970 H, 0, R066 3,514,820

TWIST LATCH Y Filed 001;. 4. 1968 I N V/SN'TOR. HERMAN 0. R066 FIG. 8 WTA TTORNE YS United States Patent 3,514,820 TWIST LATCH Herman 0. Rogg,94 Brook Drive, Watchung, NJ. 07060 Filed Oct. 4, 1968, Ser. No. 765,102Int. Cl. A44b 17/00 US. Cl. 24-221 8 Claims ABSTRACT OF THE DISCLOSURE Atwist latch having a twistable latch mounted on a base in which thelatch is urged into seating engagement on the base in either locked orunlocked position by the engagement of cam fingers in the base with aflared or tapered cam surface of a shaft on the latch.

SUMMARY OF INVENTION Twist latches are old and well known Leggo Pat. No.1,206,866 discloses a twistable latch seated by a spring. Phillips Pat.No. 1,474,208 in 1923 discloses a similar spring loaded latch. PoupitchPat. No. 2,601,213 in 1952 shows a still further development in whichcam surfaces overcome a spring washer. Seckerson Pat. No. 3,335,471 in1967 shows a locking pin for seating the twist latch.

None of these devices is especially suitable for being fabricated ofplastic materials.

The present twist latch is especially devised for fabrication of plasticmaterials and takes advantage of the inherent resiliency of the plasticmaterial to co-operate with a cam surface to seat the twist latch inlocked or unlocked condition.

A very inexpensive and durable twist latch is thereby provided which maybe fabricated very cheaply and may be easily attached to other surfacesor bodies.

The foregoing objects and advantages, as well as other objects andadvantages, may be attained by the device shown by way of illustrationin the drawings in which:

DRAWINGS FIG. 1 is a side elevational 'view of the latch portion of thetwist latch;

FIG. 2 is a top plan view of the base of the twist latch;

FIG. 3 is a vertical sectional view taken on the line 3-3 in FIG. 2looking in the direction of the arrows;

FIG. 4 is an end elevational view of the latch shown inFIG. 1;

FIG. 5 is a view in perspective of the twist latch assembly in latchingposition;

FIG. 6 is a view in perspective of the twist latch assembly with thelatch in unlocked position;

FIG. 7 is a partially sectioned view of the assembly with the latch inunlocked position; and

FIG. 8 is a view of the co-operative fasteners for attaching the twistlatch assembly to an object.

DETAILED DESCRIPTION Referring now to the drawings in detail, the twistlatch therein shown provides a handle 10 with one side relatively largerthan the other and flat to enable it to be easily seized and twisted.The twist latch 11 has a shaft 12 depending therefrom. The upper portion14 of the shaft is shown to be tapered, but this is merely a designfeature. The lower portion 15 of the shaft has a flared portion defininga cam surface. Immediately beyond the lower portion 15, there is a head13, which is generally in the shape of an inverted dome. The head 13 hasa pair of ears 16 on opposite sides. The bottom of the handle 10 of thetwist latch 11 has a longitudinal rib 17 which intersects with the shaft12 and extends on both sides of it. The upper portion of the shaft 14and the lower Patented June 2, 1970 portion 15 of the shaft define anannular seat 29 or constriction at the narrowest portion of the shaft.

The twist latch assemblage has a base 21. The base is elongated. It isnoted that the handle .10 is also elongated so that when the handle isdisposed transverse to the base, it extends beyond the base. The base 21may be slightly larger in its cross-sectional area progressively fromtop to bottom. This top enlargement 22 is generally flat and is providedwith a latitudinal channel 25 defining a seat for the twist latch 11 inlocked position, and a longitudinal channel 24 (optional) defining aseat for the twist latch 11 in unlocked position. A flange 30 defines aseat for a fastener as will be hereinafter referred to. The flange 30has a pair of slots 31. There is a top central aperture 23- on the topof the base 21. This aperture, as will be seen from FIG. 2-, isgenerally circular with opposite enlargements dimensioned suflicientlygreat to permit the insertion of the latch and to particularly pass thecars 16. Surrounding the top central aperture 23 and dependingdownwardly therefrom on opposite sides thereof, there are a pair ofresilient fingers 26. These fingers 26 are sufficiently long so thattheir lower end will be in engagement with the cam surface 15 slightlybelow the constriction or narrow point 29 when the twist latch 11 isinserted fully into the aperture 23, and the rib 17 is seated either inthe latitudinal channel 25 or the longitudinal channel 24. The fingers26 assert pressure on the cam surface 15, thereby normally urging therib 17 into seated engagement with either of the channels 24, 25 when inregistration with them, or when at an intermediate position, to bearfirmly on the top of the base 21. It will be seen that when the twistlatch 11 is turned to disengage the rib 17 from either of the channels24, 25, the shaft 12 will tend to move out of the base 21. This willtend to cause the resilient fingers 26 to ride up the flared lowersurface 15. The fingers will be deformed outwardly and by reason oftheir resiliency, will exert pressure tending to restore the twist latch11 to its normal position with the rib 17 seated in either of thechannels 24, 25, when it is positioned in registration with the channels24, 25. Thus, the latch operates through the combination of springpressure exerted by the resilient fingers and by the cam action of theresilient fingers upon the lower portion 15 of the shaft 12. The shaft12 is thereby constantly urged into the base 21 with the effect ofseating the rib 17 in locked or unlocked position in either of thechannels 24, 25. The ears 16, 16 will prevent extreme force fromwithdrawing the latch 11 from the base 21 when the latch is in anyposition except the unlocked position. In the unlocked position, extraforce and deflection of the fingers 26 to disengage them from a shoulder36 will permit the withdra'wal of the latch 11 from the base 21.

At the top of the head 13, at the point of intersection with the flaredlower surface 15, there is defined a flat shoulder 36.

In operation, with the handle 10 in locked position (FIG. 5), excessiveaxial force exerted on the handle 10 may tend to withdraw the handle 10from the base 21, except for the fact that the fingers 26 will ride downthe surface 15 until the ears 16 engage the fingers 26, therebypreventing the separation of the handle 10 and the base 21.

On the other hand, in unlocked position, theexcessive axial forceexerted on the handle 10 will cause the fingers 26 to ride up thesurface 15. Since the ears 16 may intrude between the fingers 26, thewithdrawl is in this position prevented by the fingers 26 riding downthe flared lower surface 15 into seating engagement with the shoulder36, thereby preventing the separation of the handle 10 and the base whenthe device is in unlocked position.

While I have referred to the rib 17 being on the handle and the channels24, being on the base, it is to be understood that the position of theseparts may be interchanged. The rib 17 and the channels 24, 25 need notbe as long as shown, but may be made very short as long as they engageeach other.

In order to apply the twist latch assemblage to a body, a generallyrectangular retainer 32 is provided dimen sioned to fit over and aroundthe base 21, with tabs 33 fitable into the slots 31. A retainer plate 34is also provided with notches 35 into which the tab 33 may be fitted andbent over under the plate 34, thereby to secure the latch assemblageafiirmatively to any body or sheet intruded between the base and theplate 34.

The foregoing description is merely intended to illustrate an embodimentof the invention. The component parts have been shown and described.They each may have substitutes which may perform a substantially similarfunction; such substitutes may be known as proper substitutes for thesaid components and may have actually been known or invented before thepresent invention; these substitutes are contemplated as being withinthe scope of the appended claims, although they are not specificallycatalogued herein.

What is claimed:

1. A twist latch comprising:

(a) a hollow base,

(b) an elongated handle twisted in registration with,

or transverse to, the base,

(c) a rib on the handle adjacent to the base,

(d) a transverse channel on the base positioned to seat the rib when thehandle and the base are disposed transverse with respect to each other,

(e) a shaft on the handle extending through an aperture into the base,

(f) a flared portion on the shaft defining a cam surface,

(g) a resilient finger on the base at the inside thereof, defining acam, engaging the cam surface of the shaft, and normally urging theshaft into the base to seat the rib on the bottom of the handle, in thetransverse channel.

2. The device according to claim 1, and a second resilient finger on thebase at the inside thereof, defining a cam, engaging the opposite sideof the cam surface of the shaft, and normally urging the shaft, inco-operation with the other resilient finger, into the base to seat therib on the bottom of the handle, in the transverse channel.

3. The device according to claim 2 and the resilient fingers dependinginwardly of the base from the edge of the aperture therein, coaxial withthe shaft.

4. The device according to claim 1, and

(a) a flange on the outside of the base,

(b) slots in the flange,

(c) a retainer seated on the flange,

(d) detents on the retainer extending through the slots,

(e) a notched plate,

(f) the detents deformed around the plate through the notches.

5. The device according to claim 2, and

(a) a head on the shaft defining a shoulder,

(b) the shoulder in abutment with the resilient fingers to prevent thewithdrawl of the shaft from the base when the device is unlocked.

6. The device according to claim 2, and

(a) a head on the shaft defining a shoulder,

(b) the shoulder in abutment with the resilient fingers to prevent thewithdrawl of the shaft from the base.

7. The device according to claim 1, and a longitudinal channel on thebase positioned to seat the rib when the handle and the base are inregistration in unlocked position.

8. The device according to claim 5, and ears on the head in generalvertical registration with the plane of the handle, the ears definingdetents engageable with the fingers when the handle is disposed inlocked position, whereby the handle cannot be axially withdrawn from thebase.

References Cited UNITED STATES PATENTS 717,714 1/1903 Quimby 24 9s1,474,208 11/1923 Phillips.

BERNARD A. GELAK, Primary Examiner

